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2 <br />Mr. Todd Del Frate <br />Corral Hollow Fourth Quarter and Annual 2024 Report <br /> <br /> <br />PCE and a “significantly increasing” trend for cis-1,2-DCE. Although cis-1,2- DCE continues to <br />show an increasing trend, the Third Quarter 2024 detection for cis-1,2- DCE was at its lowest <br />concentration since 2017, with a concentration slightly above the PQL at 0.53 μg/L. During <br />Fourth Quarter 2024, cis-1,2-dichloroethene was reported at a concentration of 0.78 μg/L. Cis- <br />1,2-DCE concentrations appear to be stable to slightly decreasing since 2017 when the <br />maximum historical concentration was reported (0.88 μg/L). <br />MW-8 – Concentrations of the general water quality parameters were within established <br />concentration limits, with the exception of EC, nitrate as nitrogen, and TDS. Concentrations <br />were reported within historical ranges. A “significantly decreasing” trend was reported for <br />sulfate, while "significantly increasing" trends were reported for EC, calcium, magnesium, <br />sodium, chloride, nitrate as nitrogen, and TDS. <br />Seven (7) VOCs were reported, six (6) above the PQL and one (1) below the PQL at a “trace” <br />concentration. The VOCs detected in this well were the same VOCs found in MW-5 and are <br />generally at similar to higher concentrations than observed in MW-5 this quarter. <br />Trend analysis of VOC concentrations indicated “significantly increasing” trends for chloroform, <br />1,1-DCA, and cis-1,2-DCE. Although the overall trend for chloroform is increasing, the Fourth <br />Quarter 2024 concentration was a trace concentration below the PQL (0.42 μg/L). VOC <br />1,1-DCA shows an increasing trend based on data over the past ten years, however, <br />concentrations over the past two years have been below the trend line and generally appear to <br />be decreasing in the short term. A similar trend is seen with cis-1,2-DCE. <br />Trend analysis of VOC concentrations indicated “significantly decreasing” trends for <br />dichlorodifluoromethane, PCE, trichlorofluoromethane, and Total VOCs. Total VOC <br />concentrations have generally been decreasing at this well since 2017. <br />MW-9A – Concentrations of the general water quality parameters were within established <br />concentration limits. “Significantly decreasing” trends were reported for potassium, chloride, <br />nitrate as nitrogen, and TDS while “significantly increasing” trends were reported for total <br />alkalinity, bicarbonate alkalinity and sulfate. <br />VOC trichlorofluoromethane was reported slightly above the PQL. This VOC is the only VOC <br />that has been detected in this well since 2017 and only 3 of the 20 reported detections were <br />above the PQL <br />MW-10A – Concentrations of the general water quality parameters were within the established <br />concentration limits with the exception of pH. “Significantly decreasing” trends were for <br />potassium, chloride, nitrate as nitrogen, and TDS while “significantly increasing” trends were <br />reported for total alkalinity and bicarbonate alkalinity. <br />VOCs were not detected at well MW-10A. PCE has not been detected since Third Quarter 2023 <br />(at a trace concentration) and concentrations have been below the PQL since 2021. <br />MW-11A – Concentrations of the general water quality parameters were within established <br />concentration limits with the exception of sulfate. No “significant” trends were reported. <br />Three VOCs (dichlorofluoromethane, cis-1,2-dichloroethene. and PCE) were detected with <br />concentrations consistent with historical results. The cis-1,2-DCE and PCE concentrations were